The present invention relates to a positioning system, in particular to a positioning system for use in an information recording/reproducing apparatus such as a disc player, which positioning system is adapted to ensure a needed precision in positioning a disc cartridge within a disc player.
Usually, a recording medium such as an optical disc or a photomagnetic disc is housed in a rectangular cartridge so as to be protected from an outside environment.
A disc player for recording information on or reproducing information from an optical disc, uses a laser beam to effect such recording or reproducing. When such recording or reproducing is to be conducted, a shutter of the cartridge containing an optical disc is slide open so that the optical disc is partially exposed. Then, a laser beam from an optical pickup of the optical disc player is rendered to irradiate the exposed portion of the optical disc, thereby effecting a desired information recording or reproducing.
However, to ensure a correct information recording and reproducing, it is required that the above cartridge be loaded in a correct position within the disc player.
FIGS. 9a and 9b are cross sectional views illustrating a conventional system for positioning a disc cartridge within a disc player. As shown in FIG. 9a, a plurality of positioning holes A1, A2 are formed on a disc cartridge A, a plurality of positioning pins B1, B2 are provided on the surface of a pivotable chassis B, in a manner such that the pins B1, B2 are allowed to insert into the positioning holes A1, A2, thereby rendering the cartridge A to be correctly positioned within the disc player.
Nevertheless, with such conventional positioning system, since the positioning pins B1, B2 are required to be simultaneously inserted into the positioning holes A1, A2, it is necessary that a deviation amount C for each positioning pin with respect to a corresponding positioning hole be controlled at half or less than half of the semi-diameter of the corresponding positioning hole.
Namely, if a deviation amount C for each positioning pin with respect to its corresponding positioning hole is more than half of the semi-diameter of the corresponding positioning hole, when a pressing force is exerted on the cartridge A against the chassis B, positioning pins B1, B2 may not be smoothly inserted into the positioning holes A1, A2, as shown in FIG. 9b. 
As a result, a user has to be very careful in operating the disc player to ensure that the positioning pins B1, B2 may be correctly inserted into the corresponding positioning holes A1, A2, so as to have the disc cartridge A located at a correct position in the disc player.
It is an object of the present invention to provide an improved positioning system for use in a disc player, so as to produce an improved disc player easy to operate without having to be very careful when inserting a disc cartridge into the disc player, thereby solving the above-mentioned problem peculiar to the above-mentioned prior art.
According to the present invention, there is provided an improved positioning system for use in an information recording/reproducing apparatus for positioning a cartridge containing an information recording medium on a chassis mounting information recording and reproducing means. Such positioning system comprises a plurality of positioning holes formed on the cartridge containing an information recording medium; and a plurality of positioning pins formed on the chassis mounting information recording and reading means. In particular, when a cartridge containing an information recording medium is inserted into the recording/reproducing apparatus, one of the positioning pins is caused to insert into a corresponding positioning hole earlier than the insertion of other pin(s) into other corresponding positioning hole(s).
In one aspect of the present invention, said one of the positioning pins is larger in size than other positioning pin(s), and adapted to insert into said corresponding positioning hole which is also larger in size than other positioning hole(s).
In another aspect of the present invention, each of the positioning pins is formed into a taper or hemispherical shape.
The above objects and features of the present invention will become better understood from the following description with reference to the accompanying drawings.